Mammals harbor diverse microbial species in their gastrointestinal (GI) tracts. Interactions between these microbes and between microbes and the host, e.g. the host immune system, shape a microbiota. A healthy microbiota provides the host with multiple benefits, including colonization resistance to a broad spectrum of pathogens, essential nutrient biosynthesis and absorption, and immune stimulation that maintains a healthy gut epithelium and an appropriately controlled systemic immunity. An unbalanced microbiota (also called ‘dysbiosis’ or disrupted symbiosis) may lose its function and results in increased susceptibility to pathogens, altered metabolic profiles, or induction of proinflammatory signals that can lead to local or systemic inflammation or autoimmunity. The intestinal microbiota plays a significant role in the pathogenesis of many disorders such as pathogenic infections of the gut.
Ulcerative colitis is a chronic disease of the large intestine, also known as the colon, in which the lining of the colon becomes inflamed and develops tiny open sores, or ulcers, that produce pus and mucous. Ulcerative colitis occurs most often in people ages 15 to 30, although the disease may afflict people of any age. It affects men and women equally and appears to run in some families.
Ulcerative colitis is a disease that is characterized by inflammation and micro-ulcers in the superficial layers of the large intestine. The inflammation usually occurs in the rectum and lower part of the colon, but it may affect the entire large intestine (pancolitis). Ulcerative colitis can very rarely affect the small intestine in its distal portion (Backwash Ileitis).
The inflammation is accompanied usually with diarrhea, which may be profuse and bloody. Micro-ulcers form in places where inflammation has destroyed the cells lining the bowel and these areas bleed and produce pus and mucus. Ulcerative colitis, especially when mild, can be difficult to diagnose because symptoms are similar to other intestinal disorders, most notably the other type of Irritable Bowel Diseases (IBD) called Crohn's disease and also irritable bowel syndrome. Crohn's disease differs from ulcerative colitis because it causes inflammation throughout the whole thickness of the intestinal wall and produces deep ulcers. Crohn's disease usually occurs in the small intestine, but it can also occur in the large intestine, anus, esophagus, stomach, appendix and mouth. Crohn's disease causes fistulae whereas ulcerative colitis does not. Both Crohn's and ulcerative colitis may co-exist in the same patient. The combination of inflammation and ulceration can cause abdominal discomfort and frequent emptying of the colon. Existing treatments for ulcerative colitis involve intense and lengthy combinational drug therapy with significant side effects or even require surgery to remove part of the colon. Moreover, a substantial proportion of ulcerative colitis patients are resistant to standard drug therapy. Thus, there is a need for more effective treatments for ulcerative colitis that are easier to administer.
Implantation or administration of human colonic microbiota into the bowel of a sick patient is called Fecal Microbiota Transplantation (FMT), also commonly known as fecal bacteriotherapy. FMT is believed to repopulate the gut with a diverse array of microbes that control key pathogens by creating an ecological environment inimical to their proliferation and survival. It represents a therapeutic protocol that allows a fast reconstitution of a normal compositional and functional gut microbial community.
Fecal microbiota transplantation (FMT), also known as ‘fecal bacteriotherapy,’ represents the one therapeutic protocol that allows the fastest reconstitution of a normal composition and functional gut microbial community. For many decades, FMT has been offered by select centers across the world, typically as an option of last resort for patients with recurrent Clostridium difficile infection (CDI). FMT has also been suggested in treating other gut infective agents such as E. coli and Vancomycin resistant Enterococci (VRE). Currently, FMT is administered by several routes including infusion of human microbiota in the form of homogenized stool, extracts of homogenized stool, or cultured stool components through a colonoscope, an enema, or via a nasojejunal tube.